1. Field of the Invention
The present invention relates generally to packaging techniques, and more particularly, to a multimedia chip package and a fabrication method thereof.
2. Description of the related Art
Because of the rapid development of information technology, integrated circuits have become essential for daily use. Products formed by integrated circuits appear in all aspects of daily life. Semiconductor technology is continuously developing to be more personal and functional, and complex new electronic products are constantly being developed. As a result, a major trend in the semiconductor industry is to make products even lighter, thinner, smaller and faster, while also making them friendly, convenient, powerful, reliable and increasingly less expensive.
In semiconductor fabrication, semiconductor devices are entering the submicron century by producing 0.18 xcexcm integrated circuits. As a matter of fact, a much higher-density integrated circuit now can be produced. The fabrication process of an integrated circuit can be separated into three different processes: a fabricating process of a silicon wafer, a fabricating process of an integrated circuit and a packaging process of the integrated circuit. The packaging process of the integrated circuit is the final step for completing the integrated circuit product, and the main purpose of this packaging step is to establish electrical connections from a die to a printed circuit board (PCB) or other devices. Moreover, the packaging process can protect the chips.
A multimedia chip (MMC) package consists of an application-specific integrated circuit (ASIC) controller and a flash memory. The multimedia chip package is usually very thin in order to be applied to MMC products. However, the cost of the multimedia chip package is very high, and the process yield is not good.
FIG. 1 illustrates a cross-sectional view of a conventional MMC package. FIG. 1A is a top view diagram of FIG. 1. In the conventional fabrication process of a MMC package, a substrate (not shown in the diagrams) is provided, which substrate comprises a plurality of substrate units 110 (only one substrate unit is shown in FIG. 1) and connecting bars (not shown in the diagrams). Each substrate unit 110 comprises an upper surface 112 and a corresponding lower surface 114. A plurality of external nodes 116 is located at the periphery of the upper surface 112 of the substrate unit 10 and is also called gold pins. The external nodes 116 can be electrically connected to external circuits. The lower surface 114 of the substrate unit 110 comprises a plurality of die pads and a plurality of nodes 120. At least a multimedia chip 180 has an active surface 182 and a corresponding back surface 184. A plurality of bonding pads 186 is formed on the active surface 182 of the multimedia chip 180.
A die attaching process is carried out to adhere the back surface 184 of the multimedia chip 180 onto the die pad 118 of the substrate unit 110. A plurality of conductive wires 190 electrically connects the bonding pads 186 to the nodes 120. A molding process is carried out next to encapsulate the multimedia chip 180, conductive wires 190 and portions of the lower surface 114 of the substrate units 110 with a molding compound 130. A plurality of packaging units 188 is thus formed (one of the package units is shown in the FIG. 1). Each packaging unit 188 corresponds to each substrate unit 110. A singulation process is carried out to separate each packaging unit by punching or sawing, whereby packaging units are separated from connecting bars. A quality control test is carried out to detect whether or not each packaging unit 188 passes the quality standards. A process of adding a cap to the package unit comprises the following steps. First, an adhesive material 160 is applied on the cap 150, and then the cap 150 with the adhesive material 160 covers the molding compound 130 and a portion of the lower surface 114 of the substrate unit 110. After pressing and heating processes, the cap 150 is firmly secured onto the package unit 188. Finally, a label 152 is adhered on the surface of the cap 150.
From the above-mentioned packaging process, the thickness of the substrate 110 can be approximately 0.3 mm because the thickness of the whole package unit is only approximately 1.4 mm. Therefore the thickness of the substrate has to be very thin, which leads to a warpage problem. This can also lead to a delamination problem, thus affecting the production yield and increasing the cost. The process of adding a cap to the substrate unit is complex, and the material cost of the cap 150 and the adhesive material 160 can increase the production cost. The tolerance between the cap and the package unit, and the adhesive ability between the cap, the adhesive material and the substrate unit 110 can be a problem. Excess adhesive material overflows onto the outer surface of the package unit; therefore, the reliability of the product decreases.
It is an object of the present invention to provide an improved method for packaging a multimedia chip package without a cap. Since the step of adding a cap is omitted, the whole fabrication process of the multimedia chip package is thus simplified. Therefore, the cost can be reduced, and the production yield is improved.
It is another object of the present invention to provide an improved method and fabrication process for reducing the volume of a multimedia chip package.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, a multimedia chip package is provided. The multimedia chip package comprises: a substrate unit having a first surface and a corresponding second surface, wherein a plurality of nodes and at least a die pad are formed on the first surface of the substrate unit; a plurality of external nodes is formed on the second surface of the substrate unit and electrically connected to the nodes; at least a multimedia chip having an active surface and a corresponding back surface, wherein a plurality of bonding pads is formed on the active surface of the multimedia chip, the back surface of the multimedia chip is adhered on the die pad of the substrate unit and the bonding pads are electrically connected to the nodes by a plurality of conductive wires; and a molding compound encapsulating the multimedia chip, the first surface of the substrate unit, the conductive wires, and exposing the second surface of the substrate unit and the external nodes.
According to one of the preferred embodiments of the present invention, the external nodes are located near a peripheral region of the second surface of the substrate unit. The shape of the external nodes can be rectangular and square. A label is adhered on the surface of the molding compound.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, a method of fabricating a multimedia chip package is provided, comprising the following steps. A substrate is provided, which comprises a plurality of connecting bars and at least a package unit. The connecting bars surround the periphery of the package unit, and each package unit contains a substrate unit. The substrate unit has a first surface and a corresponding second surface, and at least a die pad and a plurality of nodes are formed on the first surface of the substrate unit. A plurality of external nodes is formed on the second surface of the substrate unit, and the external nodes are electrically connected to the nodes. At least a multimedia chip is provided and has an active surface and a corresponding back surface. A plurality of bonding pads is formed on the active surface of the multimedia chip. The back surface of the multimedia chip is adhered on the die pad. A wire bonding process is carried out to electrically connect the bonding pads to the nodes. A molding process is carried out in which a mold has at least a cavity that corresponds to the packaging unit of the substrate. The packaging unit of the substrate and the multimedia chip are located in the cavity, and a molding compound is filled into the cavity. The molding compound encapsulates the first surface of the substrate unit, the multimedia chip, the conductive wires, and exposes the second surface of the substrate unit and the external nodes. A singulating process is carried out to separate the package unit of the substrate from the connecting bars of the substrate.
According to one of the preferred embodiments of the present invention, the singulating process comprises a punch method or a sawing method to separate the package unit of the substrate from the connecting bars of the substrate. After the molding process, a label is adhered on the surface of the molding compound. A test is also provided after the singulating process. The external nodes are located near a peripheral region of the second surface of the substrate unit. The external nodes are rectangular or square in shape.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, another method of fabricating a multimedia chip package is provided, comprising the following steps. A substrate is provided, which comprises a plurality of connecting bars and at least a package unit. The connecting bars surround the periphery of the package unit, and each package unit contains a plurality of substrate units. Every substrate unit has a first surface and a corresponding second surface, and at least a die pad and a plurality of nodes are formed on a first surface of each substrate unit. A plurality of external nodes is formed on a second surface of each substrate unit, and the external nodes are electrically connected to the nodes. A plurality of multimedia chips is provided, and each multimedia chip has an active surface and a corresponding back surface. A plurality of bonding pads is formed on the active surface of each multimedia chip. The back surface of each multimedia chip is adhered on the die pad. A wire bonding process is carried out to electrically connect the bonding pads to the nodes. A molding process is carried out, forming a mold having at least a cavity that corresponds to the packaging unit of the substrate. The packaging unit of the substrate and the multimedia chip are located in the cavity, and the cavity is filled with a molding compound. The molding compound encapsulates the first surface of the substrate unit, the multimedia chip, the conductive wires, and exposes the second surface of the substrate unit and the external nodes. A plurality of packaging units is thus formed. Each packaging unit corresponds to one of the substrate units and one or more of the multimedia chips. A singulating process is carried out to separate the package units of the substrate from the connecting bars of the substrate.
According to one of the preferred embodiments of the present invention, the singulating method is used to separate each packaging unit. A punch method or a sawing method is used to separate each package unit of the substrate from the connecting bars of the substrate. A test is also provided after the singulating process. After the molding process, a label is adhered on the surface of the package material. The external nodes are located near a peripheral region of the second surface of the substrate unit. The shape of the external nodes is rectangular or square.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, another multimedia chip package is provided, which comprises: a substrate unit having a first surface and a corresponding second surface, wherein a plurality of first nodes, at least a die pad and a plurality of external nodes are formed on the first surface of the substrate unit, and a plurality of second nodes and at least a second die pad are formed on the second surface of the substrate unit, and the external nodes are electrically connected to the first nodes and the second nodes; at least a first multimedia chip having a first active surface and a corresponding first back surface, wherein a plurality of first bonding pads is formed on the first active surface of the first multimedia chip, the first back surface of the first multimedia chip is adhered on the first die pad of the substrate unit, and the first bonding pads are electrically connected to the first nodes by a plurality of first conductive wires; at least a second multimedia chip having a second active surface and a corresponding second back surface, wherein a plurality of second bonding pads is formed on the second active surface of the second multimedia chip, the second back surface of the second multimedia chip is adhered on the second die pad of the substrate unit, and the second bonding pads are electrically connected to the second nodes by a plurality of second conductive wires; and a molding compound encapsulating the first multimedia chip, the second multimedia chip, the first conductive wires, the second conductive wires and a portion of first surface of the substrate unit, wherein the external nodes are exposed.
According to one of the preferred embodiments of the present invention, the molding compound can completely encapsulate the second surface of the substrate unit or partially encapsulate the second surface of the substrate unit. The side surfaces of the substrate unit can be exposed or covered. The external nodes are located near a peripheral region of the first surface of the substrate unit. The external nodes are rectangular or square in shape.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.